Area Forecast Discussion

000
FXUS61 KBGM 091133
AFDBGM
Area Forecast Discussion
National Weather Service Binghamton NY
633 AM EST Fri Dec 9 2016
.SYNOPSIS...
A cold northwest wind will persist over the region through
Saturday. Scattered snow showers and flurries will continue
through the period. Southeast of Lake Ontario more persistent and
significant lake effect snow showers will occur with several
inches of snowfall expected.
&&
.NEAR TERM /THROUGH TONIGHT/...
Secondary surface trough is dropping through the region at 09Z.
The intense lake effect snow band which was east of Lake Ontario
has now dropped south and weakened under northwest flow. The lake
effect snow warning for northern Oneida county has been cancelled
but the lake effect snow advisory for areas southeast of lake
Ontario will continue into Saturday morning.
Model soundings from BUFKIT using the NAM suggest a steady
300/310 flow will continue across the area through tonight. The
Canadian Regional which often does an excellent job with snow band
orientation agrees with this flow. Temperatures at 850mb will
remain near -15C so the differential for lake effect snow is
significant. The limiting factor with this event is shallow
moisture and lowering mixed layer. The advisory will remain up due
to persistent flow with total accumulations in the advisory area
in the 3-6 inch range. Much of this accumulation will occur early
this morning and again overnight. Steep low level lapse rates and
diurnal heating will make the activity more cellular today then
possibly more banded again overnight.
Rest of the area will see scattered flurries and snow showers
through the period with only light snow accumulations. It will
feel rather cold with strong northwest winds as temperatures max
out in the upper 20s to lowers 30s then drop into the teens
overnight.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
430 AM Update...
Lake effect streamers will still be with us Saturday, but the
main concern this period will be late Sunday into Monday with a
system that will likely bring a coating of snow and perhaps a
little wintry mix as well.
Another shortwave will pass through the region Saturday, and lapse
rates will still be fairly steep in the lowest 10 kft agl, which
will also contain the dendritic growth layer. With slightly
backing flow and shortwave passage, we will likely see some
enhancement of the lake effect bands again as well as increased
inland extent allowing Lake Erie band to stretch into Central
Southern Tier NY- Northern Tier PA. An inch or two of fluffy
accumulation will be easily attainable with those bands, and at
least scattered snow showers- flurries elsewhere. Things then go
pretty quiet Saturday night. Highs will be mainly 25-30 degree
range Saturday, followed by lows of 15-20 Saturday night.
Models have come into some agreement on low pressure system
ejecting from the Central Plains Sunday through the Eastern Great
Lakes Monday. This track will allow warm air to eventually sneak
in though first that will occur aloft before making its way to the
surface. It is appearing more likely now that a shield of snow
will break out Sunday afternoon into Sunday night, then thermal
profiles suggest potential for sleet-freezing rain working its way
in late Sunday night-Monday morning. Precip types will be very
sensitive to exact track of this system which, and while model agreement
is better, there is still uncertainty. Run-to-run trend is skewing
further north. For now, I have added freezing rain-sleet mention
to Northeast PA and as far north as the Finger Lakes to
Catskills in NY. The system also appears to scoop up adequate
moisture for the initial phase to include a coating of at least a
few inches of snow late Sunday-Sunday night, before temperatures
creep up and wintry mix comes in to limit additional accumulation
Monday morning. Regardless, the commute Monday morning could be a
bit of a mess, and this potential has been added to our local
Hazardous Weather Outlook.
Dry slot of system will overtake the region into Monday afternoon,
diminishing precipitation rates as moisture becomes shallow. Highs
Monday will be mainly mid to upper 30s, but it will take quite
awhile to get there.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
430 AM update...
The coldest air of the season still looks likely to arrive during
the second half of the week, though there is still significant
model disagreement on whether the responsible system will bring
another accumulating snow to the area around Wednesday. Either
way, temperatures are set to dive for Wednesday night-Thursday
with potential for some more lake effect snow.
Previous discussion...
The eastern trough will become more amplified during the long term
period as multiple waves carve out the base and drop it into the
Ohio Valley.
The trough dives into Ontario Province early Wednesday. Much
colder air will descend upon NY and PA for mid week, although the
very cold Arctic air slides eastward into Quebec and never gives
us a direct shot.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
A cold northwest flow will continue through the TAF period keeping
lake effect snow showers and flurries across the terminals. In
general widespread MVFR conditions are expected through this
afternoon with occasional IFR conditions through mid morning at
KRME/KSYR/KITH/KBGM. Conditions will be primarily low VFR at
KAVP/KELM. Overnight, MVFR conditions will prevail at KITH/KSYR
with VFR elsewhere.
Northwest winds at 10-15 knots with gusts to 25 knots decreasing
to around 10 knots this evening.
OUTLOOK...
Saturday...Occasional IFR or worse conditions will remain at play
for KSYR and KRME in lake-effect snow, with lingering restrictions
more transient at KITH, KELM, and KBGM. KAVP should stay primarily
VFR.
Sunday through Monday...Widespread restrictions likely developing
in light snow, a wintry mix, or light rain, depending on the time
and location.
Tuesday...Restrictions still possible in lingering lower ceilings
and snow showers, especially our central NY terminals.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...Lake Effect Snow Advisory until 7 AM EST Saturday for NYZ017-
018-036-037-044>046.
&&
$$
SYNOPSIS...RRM
NEAR TERM...RRM
SHORT TERM...MDP
LONG TERM...DJP/MDP
AVIATION...RRM